Research On Inversion Method Of Target Elevation Information For Video Synthetic Aperture Radar

The research of video synthetic aperture radar(ViSAR)related application technology is one of the most prospective topics in the field of microwave detection and imaging.ViSAR has the characteristics of high frame rate imaging,which provides a new data processing approach for moving target detection and tracking on the basis of traditional SAR data processing.According to the current application research situation of ViSAR,the inversion technology of elevation information based on ViSAR is still in the blank stage.This technology combines the advantages of high frame rate of ViSAR imaging and high precision of microwave interferometry to provide a new idea for the research of real-time high resolution target measurement technology.In this thesis,the method of generating digital elevation model(DEM)of ViSAR imaging target is studied.The main work is as follows:(1)An interference measurement model based on ViSAR is proposed.Firstly,the basic principle of ViSAR continuous frame imaging is analyzed.Secondly,according to the interferometric measurement model of interferometric synthetic aperture radar(InSAR),the principle of high precision measurement of InSAR is deduced theoretically.Then,combining the ViSAR imaging model with the InSAR interferometric measurement model,a special interferometric measurement model and data processing flow suitable for ViSAR circular mode are proposed.(2)The phase-preserving analysis of ViSAR interferometric imaging algorithm is carried out.Firstly,the influence of ViSAR interferometric phase error on DEM reconstruction accuracy is deduced.Secondly,the phase fidelity of common ViSAR imaging algorithms used in interferometric measurement is studied,and the factors causing the loss of phase accuracy of ViSAR imaging algorithm are analyzed.Then,the interferometric phase errors of common ViSAR algorithms are verified by experimental simulation.Finally,the interferogram is generated by simulating the conical model,and the difference of phase quality between back projection(BP)algorithm and polar coordinate format(PFA)algorithm for ViSAR interferometry imaging is verified.and It is found that BP algorithm is more suitable for ViSAR interferometry imaging.(3)The data processing method based on ViSAR DEM is studied.Firstly,several de-leveling methods,filtering methods and unwrapping methods are compared and studied,and a more suitable method for ViSAR interferometry processing is selected.Then,two data fusion methods for ViSAR height measurement are studied,and the effectiveness of these two methods to improve the accuracy of topographic elevation measurement is verified by cone simulation.Finally,through interference simulation of multiple mountain models and fusion of multiple interference results,a three-dimensional peak height information map without overlap is obtained,which further improves the.data processing method generated in ViSAR DEM.